==================================================================

The following Stata 7.0 commands replicate the analysis in Table 2
of:

Box-Steffensmeier, Janet M. and Christopher Zorn.  2002. "Duration
Models for Repeated Events."  Journal of Politics 64(November):
1069-1094.

The data are bs_jop.dta, and are available at Zorn's website
(http://www.emory.edu/POLS/zorn/).  For further information, 
contact Jan Box-Steffensmeier (jboxstef+@osu.edu) or Chris Zorn 
(czorn@emory.edu).

==================================================================


Begin with the data in ag_pwp.dta, and -stset- them to be elapsed-time.


=============================================================

COLUMN ONE:


. stset stop, failure(dispute) enter(time start) exit(time futime)

                id:  dyadid
     failure event:  dispute ~= 0 & dispute ~= .
obs. time interval:  (stopa[_n-1], stopa]
 enter on or after:  time starta
 exit on or before:  time futime

------------------------------------------------------------------------------
    20448  total obs.
        0  exclusions
------------------------------------------------------------------------------
    20448  obs. remaining, representing
      827  subjects
      405  failures in multiple failure-per-subject data
    20448  total analysis time at risk, at risk from t =         0
                             earliest observed entry t =         0
                                  last observed exit t =        35




. stcox democ growth allies contig capratio trade, nohr robust cluster(dyadid) efron, if firstev==1

         failure _d:  dispute
   analysis time _t:  stop
  enter on or after:  time start
  exit on or before:  time futime

Cox regression -- Efron method for ties

No. of subjects =        17158                     Number of obs   =     17158
No. of failures =          205
Time at risk    =        17158
                                                   Wald chi2(6)    =     85.12
Log likelihood  =   -1259.0273                     Prob > chi2     =    0.0000

                           (standard errors adjusted for clustering on dyadid)
------------------------------------------------------------------------------
          _t |               Robust
          _d |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       democ |  -.4236093   .1253571    -3.38   0.001    -.6693046    -.177914
      growth |  -2.202181   1.903033    -1.16   0.247    -5.932057    1.527695
      allies |  -.4501653    .164168    -2.74   0.006    -.7719288   -.1284019
      contig |   1.053904   .1769708     5.96   0.000     .7070477     1.40076
    capratio |  -.1982849   .0786134    -2.52   0.012    -.3523643   -.0442055
       trade |  -5.347849   13.73695    -0.39   0.697    -32.27178    21.57608
------------------------------------------------------------------------------




==================================================================

COLUMN TWO:



. stset stopa, fail(dispute) exit(futime) id(dyadid) enter(starta)

                id:  dyadid
     failure event:  dispute ~= 0 & dispute ~= .
obs. time interval:  (stopa[_n-1], stopa]
 enter on or after:  time starta
 exit on or before:  time futime

------------------------------------------------------------------------------
    20448  total obs.
        0  exclusions
------------------------------------------------------------------------------
    20448  obs. remaining, representing
      827  subjects
      405  failures in multiple failure-per-subject data
    20448  total analysis time at risk, at risk from t =         0
                             earliest observed entry t =         0
                                  last observed exit t =        35



. stcox democ growth allies contig capratio trade, nohr robust cluster(dyadid) efron

         failure _d:  dispute
   analysis time _t:  stopa
  enter on or after:  time starta
  exit on or before:  time futime
                 id:  dyadid

Cox regression -- Efron method for ties

No. of subjects =          827                     Number of obs   =     20448
No. of failures =          405
Time at risk    =        20448
                                                   Wald chi2(6)    =     92.92
Log likelihood  =   -2501.8834                     Prob > chi2     =    0.0000

                           (standard errors adjusted for clustering on dyadid)
------------------------------------------------------------------------------
          _t |               Robust
          _d |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       democ |  -.4394706   .1231521    -3.57   0.000    -.6808444   -.1980969
      growth |  -3.227159   1.317689    -2.45   0.014    -5.809782   -.6445371
      allies |  -.4141413   .1704406    -2.43   0.015    -.7481988   -.0800839
      contig |   1.213475   .1782591     6.81   0.000      .864094    1.562857
    capratio |  -.2142166    .081796    -2.62   0.009    -.3745337   -.0538994
       trade |  -13.16247   13.82712    -0.95   0.341    -40.26313    13.93818
------------------------------------------------------------------------------



================================================================

COLUMN THREE:

(NOTE that this uses the data in wlw.dta...).


. stcox democ growth allies contig capratio trade, nohr efron robust cluster(dyadid) strata(enum)

         failure _d:  status
   analysis time _t:  stopa
  enter on or after:  time starta
  exit on or before:  time futime

Stratified Cox regr. -- Efron method for ties

No. of subjects =       163584                     Number of obs   =    163584
No. of failures =          405
Time at risk    =       163584
                                                   Wald chi2(6)    =     93.20
Log likelihood  =   -2505.8868                     Prob > chi2     =    0.0000

                           (standard errors adjusted for clustering on dyadid)
------------------------------------------------------------------------------
          _t |               Robust
          _d |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       democ |  -.4377964   .1225015    -3.57   0.000    -.6778949   -.1976978
      growth |  -3.183038   1.302038    -2.44   0.014    -5.734986   -.6310911
      allies |  -.4093148   .1684263    -2.43   0.015    -.7394243   -.0792054
      contig |   1.202909   .1763281     6.82   0.000     .8573126    1.548506
    capratio |  -.2134611   .0813934    -2.62   0.009    -.3729892    -.053933
       trade |  -13.00088   13.71723    -0.95   0.343    -39.88615     13.8844
------------------------------------------------------------------------------
                                                            Stratified by enum




==============================================================

COLUMN FOUR:

(Again using the data in ag_pwp.dta).


. stcox democ growth allies contig capratio trade, nohr robust cluster(dyadid) efron strata(sumdisp)

         failure _d:  dispute
   analysis time _t:  stopa
  enter on or after:  time starta
  exit on or before:  time futime
                 id:  dyadid

Stratified Cox regr. -- Efron method for ties

No. of subjects =          827                     Number of obs   =     20448
No. of failures =          405
Time at risk    =        20448
                                                   Wald chi2(6)    =     34.54
Log likelihood  =   -1262.9766                     Prob > chi2     =    0.0000

                           (standard errors adjusted for clustering on dyadid)
------------------------------------------------------------------------------
          _t |               Robust
          _d |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       democ |   .1616935   .1025067     1.58   0.115     -.039216    .3626029
      growth |  -3.765688   1.063937    -3.54   0.000    -5.850966   -1.680409
      allies |   .1439907   .1079588     1.33   0.182    -.0676046    .3555859
      contig |   .2866263     .11086     2.59   0.010     .0693448    .5039079
    capratio |   .0593644   .0289335     2.05   0.040     .0026557    .1160731
       trade |   5.996793   6.504363     0.92   0.357    -6.751523    18.74511
------------------------------------------------------------------------------
                                                         Stratified by sumdisp




===============================================================

COLUMN FIVE:


. stset stop, fail(dispute) exit(futime) enter(start)

     failure event:  dispute ~= 0 & dispute ~= .
obs. time interval:  (0, stop]
 enter on or after:  time start
 exit on or before:  time futime

------------------------------------------------------------------------------
    20448  total obs.
        0  exclusions
------------------------------------------------------------------------------
    20448  obs. remaining, representing
      405  failures in single record/single failure data
    20448  total analysis time at risk, at risk from t =         0
                             earliest observed entry t =         0
                                  last observed exit t =        35




. stcox dembkt grobkt nuallies nucontig capbkt nutrade, nohr robust cluster(dyadid) efron strata(sumdisp)

         failure _d:  dispute
   analysis time _t:  stop
  enter on or after:  time start
  exit on or before:  time futime

Stratified Cox regr. -- Efron method for ties

No. of subjects =        20448                     Number of obs   =     20448
No. of failures =          405
Time at risk    =        20448
                                                   Wald chi2(6)    =     51.09
Log likelihood  =   -1549.0541                     Prob > chi2     =    0.0000

                           (standard errors adjusted for clustering on dyadid)
------------------------------------------------------------------------------
          _t |               Robust
          _d |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
      dembkt |   .0988494   .0746859     1.32   0.186    -.0475323    .2452311
      grobkt |  -3.422491    1.24152    -2.76   0.006    -5.855825   -.9891574
    nuallies |  -.2021849   .0939167    -2.15   0.031    -.3862583   -.0181115
    nucontig |   .6177551   .1036877     5.96   0.000     .4145309    .8209794
      capbkt |   .0556901   .0253086     2.20   0.028     .0060861     .105294
     nutrade |   .8118935   9.603854     0.08   0.933    -18.01131     19.6351
------------------------------------------------------------------------------
                                                         Stratified by sumdisp
